Police in Britain said Monday they have arrested a 14-year-old boy in connection with an alleged Islamic State-inspired attack plan in Australia.
The boy was arrested Saturday "on suspicion of being concerned in the commission, preparation or instigation of acts of terrorism and remains in police custody for questioning," Greater Manchester Police in northwest England said in a statement.
Australian police arrested five men in counter-terrorism raids in Melbourne on Saturday and charged one of them with conspiring to commit a terrorist act on Anzac Day on April 25, when ceremonies are held to remember Australian and New Zealand Army Corps troops who fell at Gallipoli.
One of the officers working on the case in Britain, Detective Chief Superintendent Tony Mole, said: "We have uncovered communication between an individual in the northwest and a man in Australia to what we believe is a credible terrorist threat.
"As soon as this information came to light we acted quickly with the relevant authorities here and abroad."
Police said the boy, from Blackburn in Lancashire, northwest England, had previously been arrested on April 2 after they examined electronic devices.
They stressed they had not uncovered any evidence of an imminent attack being planned in Britain.
After the arrests in Australia, police in Britain said they were reviewing security at similar events.
"We already have protective security plans in place for major Anzac events in the UK but as a sensible precaution all forces have been asked to review security arrangements at related events," said Scotland Yard's Assistant Deputy Commissioner Neil Basu.
It is understood that the review covers Anzac Day events but also commemorations for the 70th anniversary of VE Day on May 8 being attended by high-profile figures including members of the royal family.